1. Technical Field of the Invention
The present invention relates to a method of manufacturing machine parts made by means of transient liquid phase diffusion bonding. More particularly, the present invention relates to precision machine parts made of metal by means of transient liquid phase diffusion bonding in the case of assembling machine parts, which have been conventionally manufactured by means of integral molding, having a complicated and precise pipe line inside for conveying a fluid or reducing weight and also having a cylinder inside in which a small sliding member slides.
2. Description of the Background Art
A precision part having a pipe line inside for conveying a fluid and also having a moving path in which a sliding member moves, for example, a moving blade of an internal cooling type turbine, a fuel injection pipe for automobile use, a cylinder head of an internal combustion engine or a faucet used for water supply or used for sewerage has a very complicated profile and inner structure according to the characteristic of the use of the part. Therefore, when the above precision parts are manufactured, it takes a great deal of labor and time and the manufacturing cost is raised. Accordingly, most of the precision parts are manufactured by means of casting in which the lost wax process is used. Alternatively, most of the precision parts are manufactured in such a manner that a steel ingot is subject to forging so that an external form can be made and then the inside is subjected to grinding or drilling so as to form a pipe line or a moving path in which a sliding member is moved. When this machine part is manufactured, it is divided into several parts, and they are individually manufactured, and finally the individual parts are assembled to each other so that they can be formed into a product. In order to finally assemble the individual parts into a product, it is necessary to particularly enhance the machining accuracy of the parts, and at the same time it is necessary to provide a technique for assembling the product in which all parts are assembled to a final profile without leaving any gap between the parts. For the above reasons, in the case of manufacturing a steam turbine or gas turbine, the machining and assembling cost substantially amounts to half of the manufacturing cost.
Accordingly, in many cases, it is possible to manufacture a product at low cost by the conventional manufacturing method in which casting, forging and cutting are used, because know-how of manufacturing the product has been accumulated. However, as long as they follow the prior art described above, when precise machine parts are manufactured, there is a high possibility that the high cost structure, in which the product price is raised by a high manufacturing process cost, is continued in the future. The cost of a precise machine part is mainly composed of the machining cost as described above, and the material cost is relatively low. As a result, compared with the size and profile of a machine part, the price of the part is necessarily high. Actually, parts of an engine are expensive. Accordingly, the cost of the entire apparatus, into which the precise machine parts are incorporated, is remarkably raised, which could hinder the spread of an otherwise excellent technique.
In order to solve the above problems of the high manufacturing cost structure, it is necessary to reduce the manufacturing process cost, and further it is necessary to reduce personnel expenses. However, in this mature social environment, it is difficult to reduce personnel expenses. On the contrary, there is a tendency for personnel expenses to rise, as is well known. Accordingly, it is desirable to develop a technique by which the manufacturing cost of precise machine parts, which can be made by an otherwise excellent technique, is reduced so that the precise machine parts can be industrially supplied at low cost. In order to accomplish the above object, it is necessary to replace the manufacturing technique of the prior art with a new manufacturing process which is entirely different from the conventional manufacturing method.
According to the prior art in which a forged steel ingot or a cast steel ingot is subjected to cutting or drilling so as to manufacture a machine part, it is necessary for an inside pipe line to be located on a straight line which can be formed by direct drilling conducted from the outside; that is, it is impossible to machine a pile line which cannot be formed by direct drilling conducted from the outside and it is also impossible to machine a closed system which is not open to the outside. However, the prior art is not simply limited to a pipe line located on a straight line which is open to the outside, but it is impossible to manufacture a precise machine part, which has a pipe line formed by an irregular radius of curvature, a closed path filled with a fluid or a closed pipe line necessary for reducing the weight, by machining a steel ingot. The above pipe line, incapable of being manufactured by machining from the outside after the completion of manufacturing a steel ingot, cannot be manufactured by the prior art. Such a machine part therefore cannot be designed, and further it is impossible to conceive of the machine part.